Netflix's announcement, which it made via a blog post, comes five days after Verizon sent Netflix a cease and desist letter demanding that Netflix stop showing the messages, which told some subscribers that their video streams were slow because "The Verizon network is crowded right now."

Netflix said the messages, which had also shown up on other broadband networks, including AT&T, were part of a test it had been running since May. It says that after the test ends this month, it "will evaluate rolling it out more broadly."

In the rest of the blog post—one Netflix routinely publishes, along with broadband speeds for different U.S. providers—the company makes its case against having to pay broadband providers to deliver its streams to their customers. It also denies charges from Verizon and Comcast* that is is intentionally slowing down its own streams.

The Netflix ISP Speed Index aims to provide transparency and help consumers understand the Internet access they're actually getting from their ISP. The average Netflix stream is about 2 Mbps (with most streams ranging from 256Kbps to 5.8Mbps), a fraction of the bandwidth most consumers purchase from their broadband provider. Still, in some cases, people are unable to enjoy a high quality Netflix experience.

As part of this transparency campaign, we started a small scale test in early May that lets consumers know, while they're watching Netflix, that their experience is degraded due to a lack of capacity into their broadband provider's network. We are testing this across the U.S. wherever there is significant and persistent network congestion This test is scheduled to end on June 16. We will evaluate rolling it out more broadly.

Some broadband providers argue that our actions, and not theirs, are causing a degraded Netflix experience. Netflix does not purposely select congested routes. We pay some of the world's largest transit networks to deliver Netflix video right to the front door of an ISP. Where the problem occurs is at that door—the interconnection point—when the broadband provider hasn't provided enough capacity to accommodate the traffic their customer requested.

Some large US ISPs are erecting toll booths, providing sufficient capacity for services requested by their subscribers to flow through only when those services pay the toll. In this way, ISPs are double-dipping by getting both their subscribers and Internet content providers to pay for access to each other. We believe these ISP tolls are wrong because they raise costs, stifle innovation and harm consumers. ISPs should provide sufficient capacity into their network to provide consumers the broadband experience for which they pay."